diff --git a/api/core/app/apps/advanced_chat/generate_task_pipeline.py b/api/core/app/apps/advanced_chat/generate_task_pipeline.py
index a760934020..66bf62771f 100644
--- a/api/core/app/apps/advanced_chat/generate_task_pipeline.py
+++ b/api/core/app/apps/advanced_chat/generate_task_pipeline.py
@@ -341,19 +341,20 @@ class AdvancedChatAppGenerateTaskPipeline(BasedGenerateTaskPipeline, WorkflowCyc
             # get generate route for stream output
             answer_node_id = node_config['id']
             generate_route = AnswerNode.extract_generate_route_selectors(node_config)
-            start_node_id = self._get_answer_start_at_node_id(graph, answer_node_id)
-            if not start_node_id:
+            start_node_ids = self._get_answer_start_at_node_ids(graph, answer_node_id)
+            if not start_node_ids:
                 continue
 
-            stream_generate_routes[start_node_id] = StreamGenerateRoute(
-                answer_node_id=answer_node_id,
-                generate_route=generate_route
-            )
+            for start_node_id in start_node_ids:
+                stream_generate_routes[start_node_id] = StreamGenerateRoute(
+                    answer_node_id=answer_node_id,
+                    generate_route=generate_route
+                )
 
         return stream_generate_routes
 
-    def _get_answer_start_at_node_id(self, graph: dict, target_node_id: str) \
-            -> Optional[str]:
+    def _get_answer_start_at_node_ids(self, graph: dict, target_node_id: str) \
+            -> list[str]:
         """
         Get answer start at node id.
         :param graph: graph
@@ -364,33 +365,38 @@ class AdvancedChatAppGenerateTaskPipeline(BasedGenerateTaskPipeline, WorkflowCyc
         edges = graph.get('edges')
 
         # fetch all ingoing edges from source node
-        ingoing_edge = None
+        ingoing_edges = []
         for edge in edges:
             if edge.get('target') == target_node_id:
-                ingoing_edge = edge
-                break
+                ingoing_edges.append(edge)
 
-        if not ingoing_edge:
-            return None
+        if not ingoing_edges:
+            return []
 
-        source_node_id = ingoing_edge.get('source')
-        source_node = next((node for node in nodes if node.get('id') == source_node_id), None)
-        if not source_node:
-            return None
+        start_node_ids = []
+        for ingoing_edge in ingoing_edges:
+            source_node_id = ingoing_edge.get('source')
+            source_node = next((node for node in nodes if node.get('id') == source_node_id), None)
+            if not source_node:
+                continue
 
-        node_type = source_node.get('data', {}).get('type')
-        if node_type in [
-            NodeType.ANSWER.value,
-            NodeType.IF_ELSE.value,
-            NodeType.QUESTION_CLASSIFIER.value
-        ]:
-            start_node_id = target_node_id
-        elif node_type == NodeType.START.value:
-            start_node_id = source_node_id
-        else:
-            start_node_id = self._get_answer_start_at_node_id(graph, source_node_id)
+            node_type = source_node.get('data', {}).get('type')
+            if node_type in [
+                NodeType.ANSWER.value,
+                NodeType.IF_ELSE.value,
+                NodeType.QUESTION_CLASSIFIER.value
+            ]:
+                start_node_id = target_node_id
+                start_node_ids.append(start_node_id)
+            elif node_type == NodeType.START.value:
+                start_node_id = source_node_id
+                start_node_ids.append(start_node_id)
+            else:
+                sub_start_node_ids = self._get_answer_start_at_node_ids(graph, source_node_id)
+                if sub_start_node_ids:
+                    start_node_ids.extend(sub_start_node_ids)
 
-        return start_node_id
+        return start_node_ids
 
     def _generate_stream_outputs_when_node_started(self) -> Generator:
         """